MAYBE Initial complexity problem: 1: T: (Comp: ?, Cost: 1) f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(4, 0, 0, Ar_3, Ar_4, Ar_5)) (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f9(Ar_0, Ar_1, Ar_2, Ar_2, Ar_2, Ar_5)) (Comp: ?, Cost: 1) f7(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_4, Fresh_5, Ar_4, Fresh_4)) (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_2, Fresh_3, Ar_4, Fresh_2)) (Comp: ?, Cost: 1) f6(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_0, Fresh_1, Ar_4, Fresh_0)) (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Testing for reachability in the complexity graph removes the following transitions from problem 1: f7(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_4, Fresh_5, Ar_4, Fresh_4)) f6(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_0, Fresh_1, Ar_4, Fresh_0)) We thus obtain the following problem: 2: T: (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_2, Fresh_3, Ar_4, Fresh_2)) (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f9(Ar_0, Ar_1, Ar_2, Ar_2, Ar_2, Ar_5)) (Comp: ?, Cost: 1) f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(4, 0, 0, Ar_3, Ar_4, Ar_5)) (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Repeatedly propagating knowledge in problem 2 produces the following problem: 3: T: (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_2, Fresh_3, Ar_4, Fresh_2)) (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f9(Ar_0, Ar_1, Ar_2, Ar_2, Ar_2, Ar_5)) (Comp: 1, Cost: 1) f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(4, 0, 0, Ar_3, Ar_4, Ar_5)) (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(f4) = 1 Pol(f9) = 0 Pol(f10) = 1 Pol(koat_start) = 1 orients all transitions weakly and the transition f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f9(Ar_0, Ar_1, Ar_2, Ar_2, Ar_2, Ar_5)) strictly and produces the following problem: 4: T: (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_2, Fresh_3, Ar_4, Fresh_2)) (Comp: 1, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f9(Ar_0, Ar_1, Ar_2, Ar_2, Ar_2, Ar_5)) (Comp: 1, Cost: 1) f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(4, 0, 0, Ar_3, Ar_4, Ar_5)) (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Applied AI with 'oct' on problem 4 to obtain the following invariants: For symbol f4: X_2 >= 0 /\ X_1 + X_2 - 4 >= 0 /\ -X_1 + X_2 + 4 >= 0 /\ -X_1 + 4 >= 0 /\ X_1 - 4 >= 0 This yielded the following problem: 5: T: (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5)) [ 0 <= 0 ] (Comp: 1, Cost: 1) f10(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(4, 0, 0, Ar_3, Ar_4, Ar_5)) (Comp: 1, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f9(Ar_0, Ar_1, Ar_2, Ar_2, Ar_2, Ar_5)) [ Ar_1 >= 0 /\ Ar_0 + Ar_1 - 4 >= 0 /\ -Ar_0 + Ar_1 + 4 >= 0 /\ -Ar_0 + 4 >= 0 /\ Ar_0 - 4 >= 0 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5) -> Com_1(f4(Ar_0, Ar_1 + 1, Fresh_2, Fresh_3, Ar_4, Fresh_2)) [ Ar_1 >= 0 /\ Ar_0 + Ar_1 - 4 >= 0 /\ -Ar_0 + Ar_1 + 4 >= 0 /\ -Ar_0 + 4 >= 0 /\ Ar_0 - 4 >= 0 ] start location: koat_start leaf cost: 0 Complexity upper bound ? Time: 1.380 sec (SMT: 1.316 sec)